Screw cap of synthetic resin

ABSTRACT

The object of the present invention is to provide a screw cap made of a synthetic resin that always exhibits a reliable stable function of preventing unjust unsealing.  
     It includes: a cap main body ( 2 A) serving as a cap section, a cylindrical wall ( 3 A) of which is closely screwed on a bottle mouth cylinder ( 18 ) constituting a pour spout of the bottle for closely fitting thereon; and a sealing ring ( 11 ) having a second locking section ( 12 ) locked from below across a first locking section ( 20 A) formed around the outer peripheral surface of the bottle mouth cylinder ( 18 ) and connected to the lower end of the cylindrical wall ( 3 ) through a plurality of easily breakable pieces ( 7 ), wherein a plurality of second pressing slopes ( 14 ) is disposed on the upper end of the sealing ring ( 11 ) so that the plurality of second pressing slope is closely opposed to a plurality of first pressing slopes ( 9 ) disposed on the lower end of the cylindrical wall ( 3 ) so as to slidably abut against the plurality of first pressing slope from an unscrewing direction and at a tilt angle (b) that is a larger acute angle than the lead angle (a) of a helical ridge ( 19 A) of the bottle mouth cylinder ( 18 ), thereby forcibly depressing the sealing ring ( 11 ) by abutment between both the pressing slopes during the unscrewing operation of the cap main body ( 2 A).

TECHNICAL FIELD

[0001] The present invention relates to a screw cap made of a syntheticresin with a function of preventing unjust unsealing, which is joined toa pour spout of a bottle and serves as a closable cap.

BACKGROUND ART

[0002] Related art techniques of a cap having an unjust-unsealingpreventing function (pilfer-proof function) include a techniquedisclosed in Japanese Examined Utility Model Registration ApplicationPublication No. 1995-12294.

[0003] This related art exhibits the pilfer-proof function in such a waythat: a pour spout that is opened and closed by a hinged upper lid isformed; an inner lid made of a metal plate for covering to close theopening of a bottle mouth cylinder is joined to a lid main bodydetachably screwed on the bottle mouth cylinder to form a lid; a breakline is formed at the lower end of a skirted wall of the lid main body;the skirted wall is divided into an upper main section and a lowerpilfer-proof base section; the main section and the pilfer-proof basesection are connected with a plurality of breakable ribs; and a lockingprotrusion is provided on the inner face of the pilfer-proof basesection, which is locked from below across a ring-shaped locking jaw ofthe bottle mouth cylinder.

[0004] In this related art, the lid main body must be unscrewed from thebottle mouth cylinder when the inner lid is removed to unseal the bottlefirst; however, the rib is broken by the unscrewing of the lid main bodyfrom the bottle mouth cylinder, so that the pilfer-proof base section isseparated from the main body to drop to the lower part of the bottlemouth cylinder. Accordingly, with the lid main body mounted on thebottle mouth cylinder after the inner lid has been removed, thepilfer-proof base section is apart from the mounted lid main body; thus,it can be determined that the bottle has already been unsealed at thesight of this separated state.

DISCLOSURE OF INVENTION

[0005] A first invention comprises: a cap section closely screwed with acylindrical wall section to be fitted on a pour spout of a bottle havinga helical ridge cut in the outer peripheral surface; and a sealing ringhaving a second locking section to be locked from below across a firstlocking section, on the inner peripheral surface, the first lockingsection being formed around the outer peripheral surface of the pourspout positioned lower than the helical ridge with the outer endpositioned outside the helical ridge, and the sealing ring beingintegrally connected to the lower end of the cylindrical wall section ofthe cap section through a plurality of easily breakable pieces, whereina plurality of second pressing slopes is disposed on the upper end ofthe sealing ring so that the plurality of second pressing slope isclosely opposed to a plurality of first pressing slopes disposed at thelower end of the cylindrical wall section of the cap section so as toslidably abut against the plurality of first pressing slope from anunscrewing direction and at a tilt angle that is a larger acute anglethan the lead angle of the helical ridge of the pour spout constructingthe function of screwing the pour spout of the bottle and the capsection together.

[0006] With the cap section of the screw cap joined to the limit ofjoining the helical ridge provided at the pour spout of the bottle, thecap section closely seals the pour spout, and the sealing ringintegrally connected to the lower end of the cylindrical wall section ofthe cap section through the breakable pieces locks from below its secondlocking section to the first locking section formed at the outerperipheral surface of the pour spout.

[0007] When the cap section is unscrewed from this state, the sealingring cannot be moved upwards relative to the cylindrical wall section,which moves upwards, by the locking of the first locking section and thesecond locking section; thus, the breakable pieces are broken.

[0008] By the breaking of the breakable pieces, the sealing ringnormally drops and displaces due to its own weight; however, when thesealing ring does not drop by adhering to the pour spout, the firstpressing slopes of the cylindrical wall section abut against the secondpressing slopes of the sealing ring at the same time as the breaking ofthe breakable pieces or immediately thereafter, and both the pressingslopes are brought into contact with each other at a tilt angle that isa larger acute angle than the lead angle of the helical ridge of thepour spout and the helical ridge of the cap section. Therefore, thesealing ring is forcibly pushed down by the cylindrical wall section andthen surely drops owing to its own weight.

[0009] Accordingly, a reliable stable pilfer-proof function can alwaysbe exhibited.

[0010] Also, since the sealing ring can forcibly be moved downwards anddisplaced by the unscrewing operation itself of the cap section, theoperation is reliable and simple.

[0011] A second invention with the arrangement of the synthetic-resinscrew cap according to the first invention comprises: a cap main bodyserving as a cylindrical cap section with a top, which is closelyscrewed with a cylindrical wall serving as a cylindrical wall section tobe fitted on a bottle mouth cylinder serving as a pour spout having ahelical ridge cut in the outer peripheral surface; and

[0012] a short cylindrical sealing ring having a second locking sectionto be locked from below across a first locking section, on the innerperipheral surface, the first locking section being formed around theouter peripheral surface of the bottle mouth cylinder positioned lowerthan the helical ridge with the outer end positioned outside the helicalridge, and the sealing ring being integrally connected to the lower endof the cylindrical wall of the cap main body through a plurality ofeasily breakable pieces, wherein a plurality of second pressing slopesis disposed on the upper end of the sealing ring so that the pluralityof second pressing slope is closely opposed to a plurality of firstpressing slopes disposed at the lower end of the cylindrical wall of thecap main body so as to slidably abut against the plurality of firstpressing slope from an unscrewing direction and at a tilt angle that isa larger acute angle than the lead angle of the helical ridge of thebottle mouth cylinder.

[0013] With the bottle mouth cylinder itself being the pour spout andthe cap main body serving as a cap section joined to the limit ofscrewing the helical ridge cut in the outer peripheral surface of thebottle mouth cylinder, the cap main body closely seals the bottle mouthcylinder, and the sealing ring integrally connected to the lower end ofthe cylindrical wall serving as the cylindrical wall section of the capmain body through the breakable pieces locks its second locking sectionfrom below to the first locking section formed at the outer peripheralsurface of the bottle mouth cylinder.

[0014] When the cap main body is unscrewed from this state, the sealingring cannot be moved upwards by the locking of the first locking sectionand the second locking section relative to the cap main body that movesupwards; thus, the breakable pieces are broken.

[0015] The first pressing slopes of the cylindrical wall abut againstthe second pressing slopes of the sealing ring at the same time as thebreaking of the breakable pieces or immediately thereafter, and both thepressing slopes are brought into contact with each other at a tilt anglethat is a larger acute angle than the lead angle of the helical ridge ofthe cap main body. Therefore, the sealing ring is forcibly pushed downby the cylindrical wall and then surely drops owing to its own weight.

[0016] A third invention with the arrangement of the synthetic-resinscrew cap according to the first invention comprises: a pour-cap mainbody serving as a pour spout of the bottle, having a attaching cylinderfitted on and over the bottle mouth cylinder and forming a pour spout bybeing closely fitted thereon; and

[0017] an outer cap detachably screwed on the pour-cap main body andserving as a cylindrical cap section with a top for opening and closingthe pour spout of the pour-cap main body, wherein:

[0018] a first locking section is formed around the outer peripheralsurface of the attaching cylinder of the pour-cap main body;

[0019] a sealing ring is integrally connected through a plurality ofbreakable pieces to the lower end of an outer cylinder serving as acylindrical wall section of the outer cap to be fitted on the attachingcylinder of the pour-cap main body in a closed state, the sealing ringhaving a second locking section to be locked from below to the firstlocking section of the pour-cap main body; and

[0020] a plurality of second pressing slopes is disposed on the upperend of the sealing ring so that the plurality of second pressing slopeis closely opposed to a plurality of first pressing slopes disposed onthe lower end of the outer cylinder of the outer cap so as to slidablyabut against the plurality of first pressing slope from an unscrewingdirection and at a tilt angle that is a larger acute angle than the leadangle of the helical ridge of the pour-cap main body.

[0021] The outer cap serving as a cap section screwed on the pour-capmain body serving as a pour spout of the bottle, which is fitted on thebottle mouth cylinder, closely seals the pour spout of the pour-cap mainbody; and the sealing ring of the outer cap fitted on the attachingcylinder of the pour-cap main body locks from below its second lockingsection to the first locking section formed at the outer peripheralsurface of the attaching cylinder of the pour-cap main body.

[0022] When the outer cap is unscrewed from this state, the sealing ringcannot be moved upwards by the locking of the first locking section andthe second locking section relative to the outer cylinder constitutingthe cylindrical wall section of the outer cap that moves upwards; thus,the breakable pieces are broken. The first pressing slopes of the outercylinder abut against the second pressing slopes of the sealing ring atthe same time as the breaking of the breakable pieces or immediatelythereafter, and both the pressing slopes are brought into contact witheach other at the lead angle of the helical ridge of the pour-cap mainbody, that is, at a tilt angle that is a larger acute angle than thelead angle of a portion constructing the function of screwing thepour-cap main body and the outer cap. Therefore, the sealing ring isforcibly pushed down by the outer cylinder and then surely drops owingto its own weight.

[0023] A fourth invention has an arrangement in which the cylindricalwall section includes first stopping sections in combination with thefirst pressing slopes, and the sealing ring includes second stoppingsections so that they are closely opposed to the first stopping sectionsso as not to get over them from the screwing direction in combinationwith the second pressing slopes, in addition to the arrangement of thesynthetic-resin screw cap according to the first, second, or thirdinvention.

[0024] In this invention, the sealing ring cannot be turned relative tothe cylindrical wall or the outer cylinder constituting the cylindricalwall section in an unscrewing direction because of the abutment of thesecond stopping sections against the first stopping sections, so thatthe occurrence of a problem is prevented in advance in that when thesealing ring screws the cap main body or the outer cap constituting thecap section to the bottle mouth cylinder or the pour-cap main bodyconstituting the pour spout, the easily breakable pieces are broken.

[0025] Also, since the first pressing slopes and the second pressingslopes are provided using the first stopping sections and the secondstopping sections, the pressing slopes can easily be formed.

[0026] A fifth invention has an arrangement in which one of a firstcombination of the first stopping sections and the first pressing slopesand a second combination of the second stopping sections and the secondpressing slopes is formed into a protrusion and the other is formed intoa recess into which the protrusion is inserted, in addition to thearrangement of the synthetic-resin screw cap according to the fourthinvention.

[0027] The present invention has a simplified arrangement of the joiningsections of the stopping sections and the pressing slopes, and asimplified opposed arrangement of both stopping sections and bothpressing slopes, thus facilitating molding correspondingly.

[0028] A sixth invention has an arrangement in which each of the firstcombinations and the second combinations, one of which is formed into aprotrusion and the other is formed into a recess, is arranged in waveform in the circumferential direction, in addition to the arrangement ofthe synthetic-resin screw cap according to the fifth invention.

[0029] In this invention, since the first combination formed at thelower end of the cylindrical wall or the outer cylinder constituting thecylindrical wall section and the second combination formed at the upperend of the sealing ring, which have the same opposed structure, are eacharranged in wave form in the circumferential direction, the shape of thecylindrical wall section and the shape of the upper end of the sealingring have high symmetry; thus, both the stopping sections and both thepressing slopes exhibit the aforesaid function, and improve theappearance.

[0030] A seventh invention has an arrangement in which either one of thelower surface of the cylindrical wall section and the upper surface ofthe sealing ring has a protrusion extending toward the other fordecreasing the spacing between the cylindrical wall section and thesealing ring, in addition to the arrangement of the synthetic-resinscrew cap according to the first, second, third, fourth, fifth, or sixthinvention.

[0031] This invention includes a protrusion for decreasing the spacingbetween the cylindrical wall or the outer cylinder constituting thecylindrical wall section and the sealing ring; so that when the cap mainbody or the outer cap constituting the cap section is first screwed onthe bottle mouth cylinder or the pour-cap main body constituting thepour spout, the protrusion abuts against the upper surface of the othersealing ring or the lower surface of the cylindrical wall section toensure a stroke between the sealing ring and the cylindrical wallsection, thereby preventing the easily breakable pieces from bending andbroken because of a decreased stroke.

[0032] Even if the cap main body or the outer cap constituting the capsection bends slightly when the cap section is joined to the pour spout,the protrusion pushes the upper surface of the other sealing ring or thelower surface of the cylindrical wall section; therefore, the secondlocking section provided at the sealing ring of the cap section surelygets over the first locking section formed at the outer peripheralsurface of the pour spout to be locked to the first locking section frombelow.

[0033] An eighth invention has an arrangement in which a spacing intowhich the end of a hard material such as a coin can be inserted isformed between the lower edge of the cylindrical wall serving as acylindrical wall section and a neck ring provided at the lower part ofthe outer peripheral surface of the bottle mouth cylinder, in additionto the arrangement of the synthetic-resin screw cap according to thefirst, second, fourth, fifth, sixth, or seventh invention.

[0034] According to this invention, even a weak person can easily dividethe sealing ring from the bottle mouth cylinder by break-opening using afamiliar hard material such as a coin.

[0035] A ninth invention has an arrangement in which the width of thesealing ring is set to a value at which the lower end almost reaches theneck ring of the bottle mouth cylinder with it fitted on the bottlemouth cylinder, in addition to the arrangement of the synthetic-resinscrew cap according to the first, third, fourth, fifth, sixth, orseventh invention.

[0036] According to this invention, the spacing formed between the loweredge of the attaching cylinder of the pour-cap main body and the neckring is reduced to be minute by almost covering the neck ring with thelower end of the sealing ring; therefore, a hard material such as a coincannot be inserted into the spacing formed between the lower edge of theattaching cylinder and the neck ring.

[0037] Accordingly, unjust division of the pour cap using a hardmaterial can be prevented, thus improving the safety of the bottlesufficiently without failure.

[0038] A tenth invention has an arrangement in which split grooves areprovided at least at the lower end of the attaching cylinder of the pourcap, and the joining strength of the pour-cap main body to the bottlemouth cylinder is set so as to be broken off by hand in the range of notturning free relative to the bottle mouth cylinder, in addition to thearrangement of the synthetic-resin screw cap according to the third,fourth, fifth, sixth, seventh, or ninth invention.

[0039] According to this invention, the joining strength of the pour-capmain body to the bottle mouth cylinder can accurately be set in anappropriate range on the basis of the number of the split grooves andthe length and shape of the grooves; and when the screw cap serving as apour cap constituted by the pour-cap main body and the outer cap isdivided from the bottle mouth cylinder for collection, the bendingdeformation of the attaching cylinder in the direction to increase thediameter can be set in an appropriate range against the external forceto divide the pour-cap main body from the bottle mouth cylinder bybreaking by hand.

[0040] An eleventh invention has an arrangement in which a locking ridgeis provided at the lower end of the inner peripheral surface of theattaching cylinder of the pour-cap main body fitted on the bottle mouthcylinder, which is locked across the locking circumferential ridgeprovided around the outer periphery of the opening of the bottle mouthcylinder, and the locking ridge of the attaching cylinder of thepour-cap main body has an intermittent circumferential ridge structureas the means for setting the joining strength of the pour-cap main bodyto the bottle mouth cylinder, in addition to the arrangement of thesynthetic-resin screw cap according to the third, fourth, fifth, sixth,seventh, or ninth invention.

[0041] According to this invention, since the locking ridge provided atthe lower end of the inner peripheral surface of the attaching cylinderof the pour-cap main body, which is locked across the lockingcircumferential ridge of the bottle mouth cylinder, has an intermittentcircumferential ridge structure, the attaching cylinder becomes thin bythe amount corresponding to the absent locking ridge, thus being easilyincreased in diameter. Therefore when the pour-cap main body is dividedfrom the bottle mouth cylinder for collection, the bending deformationof the attaching cylinder in the direction to increase the diameter canbe set in an appropriate range against the external force to divide thepour-cap main body by breaking by hand.

[0042] The intermittent circumferential ridge structure means acircumferential ridge structure having absent portions in opposite twopositions or in plural positions with regular intervals by eliminatingthe locking ridge with the circumferential ridge structure.

[0043] A twelfth invention has an arrangement in which a spacing intowhich the end of a hard material such as a coin can be inserted isformed between the lower edge of the attaching cylinder of the pour-capmain body and the neck ring, in addition to the arrangement of thesynthetic-resin screw cap according to the third, fourth, fifth, sixth,seventh, eighth, tenth, or eleventh invention.

[0044] According to this invention, even a weak person can easily dividethe pour-cap main body from the bottle mouth cylinder by break-openingusing a familiar hard material such as a coin.

[0045] A thirteenth invention has an arrangement in which the pour-capmain body and the outer cap are colored different, in addition to thearrangement of the synthetic-resin screw cap according to the third,fourth, fifth, sixth, seventh, ninth, tenth, eleventh, or twelfthinvention.

[0046] According to this invention, since the breakable pieces arebroken and the sealing ring of the outer cap moves downwards to thedownward limit, the lower portion of the attaching cylinder of thedifferent-color pour-cap main body is exposed under the outer cap tostand out clearly; therefore, the pilfer-proof function is exhibitedmore effectively.

[0047] A fourteenth invention has an arrangement in which the pour spoutformed at the pour-cap main body is a pull-open pour spout opened bybreaking and removing an unplug section having a pull ring or the like,which is divided by breakable grooves that constructs a closed loop in asealing wall that is a bottom wall of a pour cylinder provided so as toguide the pouring of a contents liquid, in addition to the arrangementof the synthetic-resin screw cap according to the third, fourth, fifth,sixth, seventh, ninth, tenth, eleventh, twelfth, or thirteenthinvention.

[0048] According to this invention, the bottle can be closely sealedreliably and firmly until the opening of the pour spout.

BRIEF DESCRIPTION OF THE DRAWINGS

[0049]FIG. 1 is a general perspective view of a first embodiment,showing a state before a screw cap and a bottle mouth cylinder isjoined.

[0050]FIG. 2 is a half longitudinal sectional view of a cap main body,shown in FIG. 1, showing a state before it is unscrewed.

[0051]FIG. 3 is a half longitudinal sectional view of a secondembodiment of a screw cap, showing a state before a cap main body isunscrewed.

[0052]FIG. 4 is a half longitudinal sectional view of the cap main body,shown in FIG. 1, showing a state after the cap main body has beenunscrewed.

[0053]FIG. 5 is a general perspective view of a fifth embodiment of ascrew cap, showing a state before a pour cap constituted by a pour-capmain body and an outer cap is joined.

[0054]FIG. 6 is a half longitudinal sectional view of the outer cap,shown in FIG. 5, showing a state before the outer cap is unscrewed.

[0055]FIG. 7 is a half longitudinal sectional view of the outer cap,shown in FIG. 5, showing a state after the outer cap has been unscrewed.

[0056]FIG. 8 is a partially enlarged front view of a first embodiment ofthe essential parts.

[0057]FIG. 9 is a partially enlarged front view of a second embodimentof the essential parts.

[0058]FIG. 10 is a partially enlarged front view of a third embodimentof the essential parts.

[0059]FIG. 11 is a partially enlarged front view of a fourth embodimentof the essential parts.

[0060]FIG. 12 is an explanatory view for describing the operation.

[0061]FIG. 13 is a general perspective view of the fourth embodiment ofthe screw cap with a cap main body divided.

[0062]FIG. 14 is a general perspective view of a fifth embodiment of ascrew cap with an outer cap divided.

[0063]FIG. 15 is a partially enlarged front view of the fifth embodimentof the essential parts.

[0064]FIG. 16 is a general perspective view of a sixth embodiment of ascrew cap with a cap main body divided.

[0065]FIG. 17 is a general perspective view of a seventh embodiment of ascrew cap with an outer cap divided.

[0066]FIG. 18 is a general perspective view of an eighth embodiment of ascrew cap, showing a pour-cap main body.

[0067]FIG. 19 is a bottom view of a ninth embodiment of a screw cap,showing a pour-cap main body.

BEST MODE FOR CARRYING OUT THE INVENTION

[0068] Embodiments of the present invention will be describedhereinafter with reference to the drawings.

[0069] First, as a first embodiment and a second embodiment, asynthetic-resin screw cap 1, shown in FIGS. 1 to 4, will be describedwhich includes a bottle mouth cylinder 18 itself as a pour spout of abottle, to which a cap main body 2A serving as a cap section is directlyjoined.

[0070] The synthetic-resin screw cap 1 of the first embodiment, shown inFIG. 1, is a solid molding made of a polypropylene resin or alow-density polyethylene resin, and is formed such that the cap mainbody 2A serving as a cylindrical cap section having a top and a shortcylindrical sealing ring 11 are integrally connected through a pluralityof easily breakable pieces 7.

[0071] The cap main body 2A serving as a cap section is constructed incylindrical form having a top such that the upper end of a cylindricalwall 3A serving as a cylindrical wall section, which is screwed on thebottle mouth cylinder 18 having a helical ridge 19A around the outerperipheral surface through a helical ridge 5 on the inner peripheralsurface, is closed with a top plate 4 having a cylindrical plug piece 6hung from the lower surface.

[0072] As shown in FIG. 2, the cylindrical plug piece 6 is closelyfitted in the opening of the bottle mouth cylinder 18 directly, having apacking 17 mounted outside the cylindrical plug piece 6 and at the lowersurface of the top plate 4 facing the upper end face of the bottle mouthcylinder 18. In the second embodiment of FIG. 3, since an inside plug 23with a pour cylindrical piece 24 constituting a pour spout of the bottleis joined to the opening of the bottle mouth cylinder 18, thecylindrical plug piece 6 has the pour cylindrical piece 24 of the insideplug 23 fitted therein closely.

[0073] A sealing ring 11 connected to the lower end of the cylindricalwall 3A through easily breakable pieces 7 has a height to form a spacings in which the end of a hard material such as a coin can be insertedbetween it and a neck ring 21 of the bottle mouth cylinder 18 with thecap main body 2A joined to the screw limit of the bottle mouth cylinder18, and also has a second locking section 12 projecting from the innerperipheral surface thereof and locked from below across a first lockingsection 20A, the first locking section 20A being provided around theouter peripheral surface of the bottle mouth cylinder 18 positionedlower than the helical ridge 19A, with the outer end arranged outsidethe helical ridge 19A.

[0074] When the sealing ring 11 is separated from the bottle mouthcylinder 18, the end of a familiar hard material such as the peripheryof a coin is inserted into the spacing s between the sealing ring 11 andthe neck ring 21, and the sealing ring 11 is forcedly opened in thedirection to increase the diameter, thus allowing easy division.

[0075] Although both of the first locking section 20A and the secondlocking section 12 have a ridge structure in the first embodiment andthe second embodiment, shown in FIGS. 2 and 3, it is not limited tothat, but may be, for example, a recessed groove structure in which oneengages with the other.

[0076] Next, as a third embodiment, a synthetic-resin screw cap 1, shownin FIGS. 5 to 7, will be described which is a pour cap constituted by apour-cap main body 25 fitted on the bottle mouth cylinder 18 serving asa pour spout of the bottle, and an outer cap 2B serving as a capsection.

[0077] The pour-cap main body 25 constituting the pour spout of thebottle is constructed such that it is fitted on the bottle mouthcylinder 18; a screw cylinder 29 having a helical ridge 19B grooved inthe outer peripheral surface is arranged, through an inward-flanged topwall 28 on the upper end of a attaching cylinder 26, which is formed toa height to form a spacing into which the end of a hard material, suchas the periphery of a coin, can be inserted; a pour cylinder 32 having abottom having the upper end enlarged in diameter like a trumpet isconnected to the upper end of the screw cylinder 29 through an inwardflanged piece 31; and an unplug section 34 having a pull-ring or thelike and divided by a breakable groove 35 formed into a closed loop isformed on a sealing wall 33 that is a bottom wall of the pour cylinder32.

[0078] A attaching cylinder 26 fitted on the bottle mouth cylinder 18includes a locking ridge 27 at the lower end of the inner peripheralsurface for getting over and locking a locking circumferential ridge 22provided around the outer periphery of the opening of the bottle mouthcylinder 18 to constitute a portion constructing the function of lockingto the bottle mouth cylinder 18, and also forms a first locking section20B shaped like a circumferential ridge around the outer peripheralsurface of a portion facing the locking circumferential ridge 22, whichis positioned on the upper outer peripheral surface adjacent to thelocking ridge 27.

[0079] A sealing cylindrical piece 30 extending and hung from the screwcylinder 29 is closely fitted on the bottle mouth cylinder 18, therebymaking the pour-cap main body 25 join to the bottle mouth cylinder 18sufficiently closely.

[0080] The outer cap 2B serving as a cap section is formed such that amain cylinder 3 a to be screwed on the screw cylinder 29 of the pour-capmain body 25 is hung from the periphery of the top plate 4 that hangsthe cylindrical plug piece 6 to be closely fitted in the opening end ofthe pour cylinder 32 of the pour-cap main body 25; the outer cylinder 3Bto be fitted on the attaching cylinder 26 via an outer flanged piece 3 cis hung from the lower end of the main cylinder 3 a; and the sealingring 11 is connected to the lower end of the outer cylinder 3B via theeasily breakable piece 7, the sealing ring 11 having the ridge-shapedsecond locking section 12, at the inner peripheral surface, to be lockedfrom below across the first locking section 20B. The main cylinder 3 a,the outer flanged piece 3 c, and the outer cylinder 3B constitute acylindrical wall section of the outer cap 2B.

[0081] Since the sealing ring 11 has a width from the first lockingsection 20B to the neck ring 21 and an inner diameter larger than theouter diameter of the neck ring 21, the upper end thereof issubstantially in contact with the first locking section 20B, and thelower end is opposed to the outer peripheral surface of the neck ring 21in the unsealed state of FIG. 6, thus allowing it to be dropped anddisplaced without interference of the neck ring 21 when the breakablepieces 7 are broken.

[0082] The upper end of the sealing ring 11 provided at the lower end ofthe outer cap 2B is substantially in contact with the first lockingsection 20B of the pour-cap main body 25 constituting a pour spout,thereby preventing deformation of the attaching cylinder 26 by anincrease in the diameter. Therefore, even when the attaching cylinder 26is formed thin so as to easily be separated from the bottle mouthcylinder 18, frequent diameter enlargement and deformation of theattaching cylinder 26 can be prevented to achieve and maintain stablejoining of the pour-cap main body 25 to the bottle mouth cylinder 18,and also the spacing formed between the attaching cylinder 26 and theneck ring 21 is covered, thereby disabling unjust process of directlyand forcibly opening the pour-cap main body 25.

[0083] Also, the minimum inner diameter of the sealing ring 11 includingthe second locking section 12 is set larger than the outer diameter ofthe neck ring 21; therefore, when the breakable pieces 7 are broken, thesealing ring 11 can be displaced downwards lower than the neck ring 21owing to its own weight, as shown in FIG. 7, thereby preventing theoccurrence of a trouble in that the second locking section 12 is caughtby the neck ring 21, and so the upper end of the sealing ring 11sheathes the lower end of the attaching cylinder 26 to disable thediameter enlargement and deformation of the attaching cylinder 26.

[0084]FIG. 8 shows the first embodiment of the essential parts of thepresent invention, which includes a plurality of first combinations offirst stopping sections 8 and first pressing slopes 9 at the lower endof the cylindrical wall 3A or the outer cylinder 3B, which forms thecylindrical wall section of the cap main body 2A or the outer cap 2Bserving as a cap section, respectively. A plurality of secondcombinations 15 of second stopping sections 13 for the first stoppingsections 8 and second pressing slopes 14 for the first pressing slopes 9is provided at the upper end of the sealing ring 11. In FIG. 8, one ofthe first combinations 10 is formed into a protrusion; on the otherhand, one of the second combinations 15 is formed into a recessed shapebetween two protrusions.

[0085] In the second embodiment of the essential parts, shown in FIG. 9,one of the first combinations 10 is formed into a recessed shape; on theother hand, one of the second combinations 15 is formed into aprotrusion.

[0086] In the third embodiment of the essential parts of the presentinvention, shown in FIG. 10, one of the first combinations 10 is formedinto a protrusion; on the other hand, one of the second combinations 15opposite thereto is formed into a recessed shape, contrarily to thesecond embodiment of the essential parts shown in FIG. 9.

[0087] In the first embodiment of the essential parts, shown in FIG. 8,a relatively large spacing is formed between the cylindrical wall 3A orthe outer cylinder 3B serving as a cylindrical wall section and thesealing ring 11, thus allowing decreasing the amount of a syntheticresin material required for molding the cap main body 2A or the outercap 2B correspondingly. On the other hand, in the case of the second andthird embodiments of the essential parts, shown in FIGS. 9 and 10, theeasily breakable pieces 7 can be formed short, thus facilitating moldingcorrespondingly.

[0088] The first stopping sections 8 and the second stopping sections 13disable the rotating displacement of the sealing ring 11 in the unscrewdirection relative to the cap main body 2A or the outer cap 2B by themutual abutment to integrally rotate them in the screwing direction whenthe cap main body 2A or the outer cap 2B serving as a cap section isfirst screwed on the bottle mouth cylinder 18 or the pour-cap main body25 serving as a pour spout of the bottle, thereby allowing the secondlocking section 12 to forcibly get over the first locking section 20A orthe first locking section 20B.

[0089] In a fourth embodiment of the essential parts of the presentinvention, shown in FIG. 11, a protrusion 16 is provided at the bottomof the first combinations 10 that is the lower surface of thecylindrical wall 3A or the outer cylinder 3B so as to face the uppersurface of the sealing ring 11, for decreasing the spacing between thecylindrical wall 3A or the outer cylinder 3B and the sealing ring 11.The protrusion 16 abuts against the upper surface of the sealing ring 11when the cap main body 2A or the outer cap 2B is first screwed on thebottle mouth cylinder 18 or the pour-cap main body 25 to ensure a strokebetween the cylindrical wall 3A or the outer cylinder 3B and the sealingring 11, thereby preventing the easily breakable pieces 7 from bendingto be broken because of a decrease in the stroke.

[0090] Even if the cap main body 2A or the outer cap 2B bends slightlywhen the cap main body 2A or the outer cap 2B is screwed on the bottlemouth cylinder 18 or the pour-cap main body 25, the protrusion 16presses the upper surface of the sealing ring 11, and the second lockingsection 12 gets over the first locking section 20A or the first lockingsection 20B without fail to lock the first locking section 20A or thefirst locking section 20B from below.

[0091] The first pressing slopes 9 and the second pressing slopes 14(hereinafter, refer to FIG. 12) are brought into contact with each otherat a tilt angle b that is an acute angle larger than the lead angle a ofthe helical ridge 5 and the helical ridge 19A or the helical ridge 19Bwhen the screw cap 1 is first turned in the unscrew direction.Accordingly, when the first pressing slopes 9 move in the direction of ealong the lead angle a in the turning range of the screw cap 1 where theabutment of both the pressing slopes is completed (the breakable pieces7 have been broken at the start of the turning range), the secondpressing slopes 14 are pushed down to move downwards in the direction off.

[0092] In other words, the cap main body 2A or the outer cap 2B movesupwards by the distance c along the lead angle a; on the other hand, thesealing ring 11 cannot move upwards by the locking of the second lockingsection 12 to the first locking section 20A or the first locking section20B. Therefore, the sealing ring 11, which cannot turn with the cap mainbody 2A or the outer cap 2B, is pushed down relative to the cap mainbody 2A or the outer cap 2B by a distance d larger than the distance calong the tilt angle b.

[0093] As described above, the sealing ring 11 is forcedly pushed downby the distance d from the cap main body 2A or the outer cap 2B.Therefore, even if the sealing ring 11 is adhered due to damp or thelike to the first locking section 20A of the bottle mouth cylinder 18 orthe first locking section 20B of the pour-cap main body 25 in theposition where the second locking section 12 is locked to the firstlocking section 20A or the first locking section 20B, the sealing ring11 is surely separated from the first locking section 20A or the firstlocking section 20B, and moves downwards owing to its own weight.

[0094] For the first combinations 10 of the first stopping sections 8and the first pressing slopes 9 and the second combinations 15 of thesecond stopping sections 13 and the second pressing slopes 14, it iseasiest to provide a plurality of ones having the same structureat-intervals along the circumference, as in the fourth embodiment of thescrew cap of FIG. 13 or the fifth embodiment of the screw cap of FIG.14.

[0095] Also, as in the fifth embodiment of the essential parts of thepresent invention, shown in FIG. 15, when an opposed pair of firstcombinations 10 and 15 is arranged in the form of wave in thecircumferential direction, the shape of the lower end of the cylindricalwall 3A or the outer cylinder 3B and the shape of the upper end of thesealing ring 11 have high symmetry, thus improving the appearance andthe design.

[0096] On the other hand, as in a sixth embodiment of a screw cap ofFIG. 16 or a seventh embodiment of a screw cap of FIG. 17, a pair ofopposed combinations is formed of a combination of a protrusion that isslightly long in the circumferential direction and a recessed portion,so that a cut taper for a separate die can be formed at thecircumferentially long joined portion, thereby allowing constructing acavity mold of a mold assembly for molding the cap main body 2A and theouter cap 2B with a simple split mold without the requirement for aslide core.

[0097] When the screw cap constituted by the pour-cap main body 25 andthe outer cap 2B is divided from the bottle mouth cylinder 18, thepour-cap main body 25 may be forcedly broken off with the outer cap 2Bscrewed thereon; however, the screw cap 1 that is a pour cap can easilybe divided by inserting the end of a familiar hard material such as theedge of a coin into the spacing between the attaching cylinder 26 andthe neck ring 21.

[0098] Also, as in the pour-cap main body 25 of an eighth embodiment ofthe screw cap, shown in FIG. 18, split grooves 27 a are provided at thelower end of the attaching cylinder 26 having the locking ridge 27; andthe joining strength of the pour-cap main body 25 to the bottle mouthcylinder 18 is set so as to allow breaking-off by hand in the range ofnot turning free relative to the bottle mouth cylinder 18.

[0099] For the attaching cylinder 26, the split grooves 27 a areincreased in diameter by the action of the breaking-off by hand, so thatthe attaching cylinder 26 bends to be deformed sufficiently; therefore,even a weak person can smoothly divide by breaking off the bottle mouthcylinder 18 of the screw cap 1 that is a pour cap constituted by thepour-cap main body 25 and the outer cap 2B.

[0100] When the split grooves 27 a are formed, it is necessary to designnot only the number but also the length, the width and so on inconsideration of the structure of the whole bottle and the condition ofuse so that the joining strength of the pour-cap main body 25 to thebottle mouth cylinder 18 is in an appropriate range and also in a rangeto allow the pour-cap main body 25 to be broken off by the weak actionof breaking-off.

[0101] As in the pour-cap main body 25 that is-a ninth embodiment of ascrew cap, shown in FIG. 19, with a structure in which the locking ridge27 of the attaching cylinder 26 intermittently projects around theperiphery, the attaching cylinder 26 becomes thin only at portions wherethe locking ridge 27 is absent, thus easily increasing in diameter.Accordingly, even a weak person can smoothly break off the screw cap 1from the bottle mouth cylinder 18.

[0102] The locking ridge 27 must have an intermittent circumferentialridge structure in which the locking ridge 27 is eliminated at twoopposite portions or a plurality of portions with regular intervals inconsideration of the condition of use and so on so that the joiningstrength of the pour-cap main body 25 to the bottle mouth cylinder 18 isin an appropriate range and also in a range to allow the pour-cap mainbody 25 to be broken off by the weak action of breaking-off.

[0103] In addition, it is also possible to easily divide the pour-capmain body 25 from the bottle mouth cylinder 18 by inserting a familiarhard material such as a handle of a spoon into the opening of the unplugsection 34 after pulling a pullring, catching one end of the hardmaterial in the inward-flanged sealing wall 33, and lifting up thepour-cap main body 25 by the action of lever of the hard material.

INDUSTRIAL APPLICABILITY

[0104] As described above, it is a technical object of the presentinvention to drop and displace a portion of a pilfer-proof cap, whichcorresponds to a pilfer-proof base section, when a lid main body isunscrewed by breaking a portion corresponding to a rib, thus exhibitingthe pilfer-proof function without fail.

1. A synthetic-resin-screw cap comprising: a cap section closely screwedwith a cylindrical wall section onto a pour spout of a bottle having ahelical ridge cut in the outer peripheral surface; and a sealing ringhaving a second locking section on the inner peripheral surface forgetting over and locking a first locking section from below, the firstlocking section being formed around the outer peripheral surface of thepour spout positioned lower than the helical ridge with the outer endpositioned outside the helical ridge, and the sealing ring beingintegrally connected to the lower end of the cylindrical wall sectionthrough a plurality of easily breakable pieces, wherein a plurality ofsecond pressing slopes is disposed on the upper end of the sealing ringso that the plurality of second pressing slope is closely opposed to aplurality of first pressing slopes disposed on the lower end of thecylindrical wall section so as to slidably abut against the plurality offirst pressing slope from an unscrewing direction and at a tilt anglethat is a larger acute angle than the lead angle of the helical ridgeconstructing the function of screwing the pour spout and the captogether.
 2. A synthetic-resin screw cap according to claim 1,comprising: a cap main body serving as a cylindrical cap section with atop closely screwed with a cylindrical wall serving as a cylindricalwall section onto a bottle mouth cylinder serving as a pour spout havinga helical ridge cut in the outer peripheral surface; and a shortcylindrical sealing ring having a second locking section, on the innerperipheral surface, to be locked from below across a first lockingsection, the first locking section being formed around the outerperipheral surface of the bottle mouth cylinder positioned lower thanthe helical ridge with the outer end positioned outside the helicalridge, and the sealing ring being integrally connected to the lower endof the cylindrical wall through a plurality of easily breakable pieces,wherein a plurality of second pressing slopes is disposed on the upperend of the sealing ring so that the plurality of second pressing slopeis closely opposed to a plurality of first pressing slopes disposed onthe lower end of the cylindrical wall so as to slidably abut against theplurality of first pressing slope from an unscrewing direction and at atilt angle that is a larger acute angle than the lead angle of thehelical ridge.
 3. A synthetic-resin screw cap according to claim 1,comprising: a pour-cap main body having a attaching cylinder gettingover and fitted on the bottle mouth cylinder and forming a pour spout bybeing closely fitted; and an outer cap serving as a cylindrical capsection with a top for opening and closing the pour spout, wherein afirst locking section is formed around the outer peripheral surface ofthe attaching cylinder; a sealing ring is integrally connected to thelower end of an outer cylinder through a plurality of easily breakablepieces, the outer cylinder serving as a cylindrical wall section of theouter cap to be fitted on the attaching cylinder in a closed state, andthe sealing ring having a second locking section to be locked from belowto the first locking section, wherein a plurality of second pressingslopes is disposed on the upper end of the sealing ring so that theplurality of second pressing slope is closely opposed to a plurality offirst pressing slopes disposed at the lower end of the outer cylinder soas to slidably abut against the plurality of first pressing slope froman unscrewing direction and at a tilt angle that is a larger acute anglethan the lead angle of the helical ridge of the pour-cap main body.
 4. Asynthetic-resin screw cap according to claim 1, 2, or 3, wherein thecylindrical wall section includes first stopping sections in combinationwith the first pressing slopes, and the sealing ring includes secondstopping sections in combination with the second pressing slopes, thesecond stopping sections being closely opposed to the first stoppingsections so as not to get over them from the screwing direction.
 5. Asynthetic-resin screw cap according to claim 4, wherein one of a firstcombination of the first stopping sections and the first pressing slopesand a second combination of the second stopping sections and the secondpressing slopes is formed into a protrusion, and the other is formedinto a recess into which the protrusion is inserted.
 6. Asynthetic-resin screw cap according to claim 5, wherein each of thefirst combinations and the second combinations, one of which is formedinto a protrusion and the other is formed into a recess, is arranged inwave form in the circumferential direction.
 7. A synthetic-resin screwcap according to claim 1, 2, 3, 4, 5, or 6, wherein either one of thelower surface of the cylindrical wall section and the upper surface ofthe sealing ring has a protrusion extending toward the other fordecreasing the spacing between the cylindrical wall section and thesealing ring.
 8. A synthetic-resin screw cap according to claim 1, 2, 4,5, 6, or 7, wherein a spacing into which the end of a hard material suchas a coin can be inserted is formed between the lower edge of thecylindrical wall serving as a cylindrical wall section and a neck ringprovided at the lower part of the outer peripheral surface of the bottlemouth cylinder.
 9. A synthetic-resin screw cap according to claim 1, 3,4, 5, 6, or 7, wherein the width of the sealing ring is set to a valueat which the lower end almost reaches the neck ring of the bottle mouthcylinder while being fitted on the bottle mouth cylinder.
 10. Asynthetic-resin screw cap according to claim 3, 4, 5, 6, 7, or 9,wherein split grooves are provided at least at the lower end of theattaching cylinder, and the joining strength of the pour-cap main bodyto the bottle mouth cylinder is set so as to be broken off by hand inthe range of not turning free relative to the bottle mouth cylinder. 11.A synthetic-resin screw cap according to claim 3, 4, 5, 6, 7, or 9,wherein a locking ridge is provided at the lower end of the innerperipheral surface of the attaching cylinder to be fitted on the bottlemouth cylinder, the locking ridge being locked across the lockingcircumferential ridge provided around the outer periphery of the openingof the bottle mouth cylinder, and the locking ridge of the attachingcylinder has an intermittent circumferential ridge structure as themeans for setting the joining strength of the cap main body to thebottle mouth cylinder.
 12. A synthetic-resin screw cap according toclaim 3, 4, 5, 6, 7, 9, 10, or 11, wherein a spacing into which the endof a hard material such as a coin can be inserted is formed between thelower edge of the attaching cylinder and the neck ring provided at thelower part of the outer peripheral surface of the bottle mouth cylinder.13. A synthetic-resin screw cap according to claim 3, 4, 5, 6, 7, 9, 10,11, or 12, wherein the pour-cap main body and the outer cap are coloreddifferent.
 14. A synthetic-resin screw cap according to claim 3, 4, 5,6, 7, 9, 10, 11, 12, or 13, wherein the pour spout formed at thepour-cap main body serving as a pour cap section is a pull-open pourspout opened by breaking and removing an unplug section having a pullring or the like, which is divided by a breakable groove constructing aclosed loop in a sealing wall that is a bottom wall of a pour cylinderprovided in order to guide the pouring of a contents liquid.